Power-operated tweezers



Patented June 1, 1937 UNITED STATES PATENT OFFICE POWER-OPERATED TWEEZERS California Application March 13, 1935, Serial No. 10,861

4 Claims.

This invention relates generally to tweezers such as are employed for plucking hair, and particularly to tweezers which are driven from an available source of power so as to be substantially automatic in operation.

It is an object of the invention to provide a device of the above character which can be readily handled by an operator and which will make possible rapid plucking action with a minimum of discomfort to the subject.

Further objects of the invention can bebriefly outlined as followsz-To minimize noise and vibration, such as are common with powerdriven appliances; to 'afiord a. simple constructiorr which can be readily manufactured and assembled; and to afford a device which will give long useful service with a minimum of maintenance and repair expense.

Additional objects of the invention will appear fromthe following description in which the preferred embodiment of the invention has been set forth in detail in conjunction with the accompanying drawings.

Referring to the drawings:

Fig. 1 illustrates my complete device, including an electrically driven pneumatic pulsator.

Fig. 2 is a cross-sectional detail illustrating connections between the electric motor and other moving parts of the pulsator.

Fig. 3 is a longitudinal cross-section, illustrating the applicator which is utilized in conjunction with the pulsator of Fig. 1.

Fig. 4 is a cross-sectional view similar to Fig. 3, but showing a difierent operating position for 5 the parts. v

Fig. 5 is an end view of the applicator, looking towards the forward end of the casing or mount ing from which the tweezer elements project.

Fig. -6 is across-sectional detail taken along the line 66 of Fig. 4.

Referring first to Fig. 1, my device consists generally of a pulsator I0, connected by a flexible' tube l'l man applicator l2. In most instances it isdesirable to have the pulsator mounted upon asuitable-portable stand, so that it can be readily'shifted to a convenient operating position.

The pulsator may vary-in details of construction, but in the instance illustrated it consists of an electrical motor l3 carried within a suitable housing 14. By means of an electrical switch !5 the motor can be stopped and started desired. Y The parts driven by the motor include a flexible diaphragm l6, the marginal edge of which is iclamped to an annular shoulder H by means of a removabledcme or closure cap I 8.

Thus, on one side of the diaphragm it there is a closed air chamber I9, which is in communi cation with the flexible tube l I.

Attached to the center of diaphragm Hi there is a rod 2|, which in turn connects to an eccentric mechanism driven by the motor. Thus the motor shaft 22 is shown provided with a worm 23, which engages the worm gear 24. Gear 24 is shown carried by a shaft 26, which also carries the eccentrics 21. A fork 28 is shown journaled upon the eccentrics 2i, and is connected to the rod 2 I. Thus when the motor I3 is operated, diaphragm i6 is vibrated at a suitable rate, as for example about 505 com plete cyclic movements per minute. Rod 2! may carry a cup washer 29, engaging the outer face of diaphragm IE to avoid detrimental abrupt flexing of the same.

The applicator 12 has been illustrated in detail in Figs. 3 to 6 inclusive. hollow, elongated casing '3l, which can be readily grasped by the hand of an operator and which forms a mounting for the moving parts. This casing can be formed of suitable light material, such as bakelite. The rear end portion 32 of the casing 3| is in the form of a removable closure cap and serves to grip the marginal edge of a flexible diaphragm 33. The flexible tube II can be attached to the coupling tube 34, which in turn communicates with the closed air chamber 36 behind the diaphragm 33. As will be presently explained, it is desirable, but not essential, to afiford a pressure spring 3'4 behind the diaphragm 33, tending to flex this diaphragm forwardly in the position shown in Fig. 3.

In the forward end portion'of the casing 3|,a longitudinal opening 38 is provided, which preferably has parallel side walls and which can be conveniently square in transverse cross-section. Fitted within the opening 38 there is a slide block 39. This block forms a. mounting for a pain of projecting tweezer elements 4! and 42, which serve as the operating elements for gripping and plucking hair. Thus, tweezer element 4| is shown attached to the outer end portion of block 39 by rivets or screws 43, while tweezer element 42 is received in a longitudinal slot 44 and is pivotally connected to the block by means of pin 46. The outer co-operating ends 4'! and 48 of the elements 4| and 42 may therefore move laterally relative to each other, to grip and release the hair. The inner co-operating faces 49 of the end portions 41 and 48 are preferably provided with interfitting grooves or corrugations,

It consists of a as shown in Figs. 3 and 4, so as to afford a better grip upon individual hairs, and to facilitate the release of a gripped hair when the end portions 41 and 48 are moved apart.

The tweezer element 42, instead of terminating adjacent the pivot pin 46, is extended inwardly to form in effect an arm 5|. By means of a linkage mechanism designated generally at 52, arm 5| is operatively connected to an actuating member or rod 53, which has its rear end attached to the center of diaphragm 33. While various forms of linkage mechanism may be available, the type illustrated utilizes a lever 54, having its one end provided with a pivotal connection 56 to the forward end of rod 53. The other end of lever 54 is pivotally connected to a pin 51, which in turn is carried by the slide block 39. The line of centers of pins 56 and 51 is generally at right angles to the direction of sliding movement afiorded between block 39 and the casing 3|. Lever 54 also carries a forwardly projecting arm 58, which, by means of a pivotal connection 59, is attached to one end of a link 6|. The other end of link 6| has a pivotal connection to the rear end of arm 5|. With this type of linkage mechanism, it is evident that when rod 53 moves rearwardly with respect to casing 3| lever 54 and also arm 58 are rotated in a clockwise direction, to swing arm 5| about its pivot 46 in a counter-clockwise direction and thus bring the end portions 41 and 48 of the tweezer elements into hair-gripping position. It is likewise evident that continued rearward movement of rod 53, since it can effect no further movement of arm 5|, serves to slide the block 39, together with the tweezer elements and other parts carried by the same, rearwardly into the casing. Conversely, when rod 53 is moved forwardly, its initial movement causes the tweezer elements to move to released position, and then further forward movement of rod 53 causes the block 39 and the tweezer elements to be slid forwardly relative to the casing. Thus, reciprocation of rod 53, through proper limits, serves to move the tweezer elements between hairgripping and released positions, and in synchronism with such movements the tweezer elements are caused to be continuously projected and retracted with respect to the casing 3|.

In order to insure proper gripping pressure between the tweezer elements, it is desirable to afford frictioning means acting between the block 39 and the adjacent walls of the casing 3|. Such frictioning means has been shown in Fig. 6, in which one side of the block 39 is provided with a recess 66 serving to accommodate a spring 61. This spring is normally under tension so as to frictionally press against the adjacent inner side wall 68 of the casing. Smoother and more reliable operation is also afforded by providing a spring or like bias tending to urge the rod 53 rearwardly relative to the block 39. For this purpose a light compression spring 69 has been shown surrounding rod 53, with the forward end of the spring seated upon the rear end of the slide block 39, and with the rear end of the spring seated upon a fitting 1| which serves to connect the rod 53 to the diaphragm 33.

It has been found desirable to aiford some means for ejecting plucked hair from between the tweezers immediately following movement of the tweezers to open position. For this purpose a small tube 12 is shown, having its forward open end terminating between the tweezer elements 4| and 42 and immediately behind the end portions 41 and 48. As shown in Fig. 6, this tube 12 extends through the forward end portion of block 39 and has its inner end communicating with a slot 13, which in turn extends rearwardly and communicates with the space 14 surrounding the inner end of the slide block. Pressure variations set up in space 14 during operation of the device, by virtue of continued flexing movements of diaphragm 33, accompanied by the more or less out-of-phase reciprocation of block 39, causes recurrent puffs of air to be discharged from the outer end of tube 12, which are so timed as to blow between the end portions 41 and 48 of the tweezer elements at the time these elements move toward release position.

Operation of my device can now be reviewed as followsz-The applicator described with reference to Figs. 3 to 6, inclusive, is connected to the flexible tube H and the motor |3 started in operation. Repeated flexing of diaphragm Is, by operation of the motor, causes air trapped in spaces l9 and 36 and within the tube II, to be recurrently compressed and rarefied. Thus, diaphragm 33 of the applicator is likewise recurrently flexed, in synchronism with the flexing movement of diaphragm l6. Recurrent flexing of diaphragm 33 causes reciprocation of rod 53, to effect the desired operation of the tweezer elements 4| and 42. To briefly review a cycle of operation, commencing with the rod 53 in the position shown in Fig. 3, during the initial part of rearward movement of rod 53 block 39 remains stationary with respect to the casing 3|, but rotation of lever 54 forces arm 53 upwardly, as viewed in this figure, to close the tweezer elements. Following such closing of the tweezer elements, continued rearward movement of rod 53 serves to slide the block 39 inwardly with respect to the casing, to effect retraction of the tweezer elements and consequent plucking of the hair gripped. Full rearward movement of rod 53 is illustrated in Fig. 4. Now, as the rod 53 starts forwardly, the first part of its movement rotates lever 54, to swing arm 5| downwardly and thus move the tweezer elements to open or release position. Further continued forward movement of rod 53 causes the block 39 to be slid forwardly, with a projection of the open tweezer elements for a new gripping operation. As has been previously explained, this operation takes place at a relatively high speed, and when the elements are so operated discomfort to the subject is minimized.

With a device constructed as disclosed herein, it has been noted that the suction or rarefaction stroke of the diaphragm l6 appears to exert more force upon diaphragm 33 than the compression stroke. It is for this reason that compression spring 31 has been inserted, to tend to equalize reciprocating forces upon rod 53 for both suction and compression strokes.

A desirable characteristic of my device is that it operates with a relatively small amount of noise and vibration, which I attribute to the fact that power is supplied to the applicator pneumatically rather than by direct mechanical connection. lneumatic operation is also deemed more desirable than a flexible mechanical drive, because it enables a material simplification in construction, with a long useful life, and without necessity of frequent servicing and repair.

The subject matter disclosed but not claimed herein, is claimed in my co-pending application, Serial No. 48,203, filed Nov. 4, 1935.

I claim:

1. In a device of the character described, a pair of tweezer elements having co-operating hairgripping end portions, a hollow elongated casing adapted to be grasped by an operator, a block slidably carried within one end portion of said casing, for reciprocating movement in a longitudinal direction, means serving to attach one of said tweezer elements to said block, means forming a pivotal connection between said block and the other one of said tweezer elements, said last-named tweezer element having an arm. secured to the same extending rearwardly within the casing, an actuating member mounted in the rear portion of the casing, means serving to rapidly reciprocate said actuating member in a direction longitudinally with respect to the easing, a lever serving to pivotally connect the forward end of said actuating member to said block, an arm carried by said lever, and a link serving to pivotally connect said last-mentioned arm with the inner end of said first-mentioned arm, said first-mentioned arm having limited pivotal movement whereby reciprocation of said actuating member effects sliding movement of said block and also causes relative lateral movement between said tweezer elements.

2. In a device of the character described, a hollow elongated casing adapted to be grasped by the hand of an operator, a pair of tweezer elements slidably carried within the forward end of said casing and projecting therefrom, a diaphragm mounted within the rear end portion of said casing, there being a closed chamber behind said diaphragm adapted to receive periodically varying pneumatic pressures, an actuating member within the mounting, one end of said member being secured to said diaphragm and the other end of said member extending forwardly within the mounting towards said tweezer elements, and mechanism serving to co-operatively connect said member with said tweezer elements and serving to reciprocate the same relative to the mounting and to efiect relative lateral movement between the hair-engaging ends of the same.

3. In a device of the character described, a hollow elongated casing adapted to be grasped by an operator, a pair of tweezer elements, means serving to slidably mount said tweezer elements in the forward end portion of said mounting, said last means also enabling relative pivotal movement of said elements between hair-gripping and release positions, actuating means carried within the rear portion of said mounting and serving to effect longitudinal reciprocation of said tweezer elements in synchronism with relative lateral movement of the tweezer elements between hair-gripping and release positions, and means for directing a stream of air between the hair-gripping portions of said tweezer elements.

4. In a device of the character described, a pair of tweezer elements having cooperating hair gripping end portions, a hollow elongated casing adapted to be grasped by an operator, a block slidably carried within one end portion of said casing, for reciprocating movement in a longitudinal direction, means serving to attach one of said tweezer elements to said block, means forming a pivotal connection between said block and the other one of said tweezer elements, said last named tweezer element having an arm secured to the same extending rearwardly within the casing, a flexible diaphragm mounted within the rear end portion of the casing, there being a closed chamber behind said diaphragm adapted to receive periodically varying pneumatic pressures, an actuating member mounted in the casing and having its rear end connected to said diaphragm, a lever serving to pivotally connect the forward end of said actuating member to said block, an arm carried by said lever, and a link serving to pivotally connect said last mentioned arm with the inner end of said first mentioned arm, said first mentioned arm having limited pivotal movement whereby reciprocation of said actuating member efiects sliding movement of said block and also causes relative lateral movement between said tweezer elements.

FLOYD V. SCI-ILEIMER. 

